1. Field of the Invention
The present invention pertains to headgear for use in securing devices, such as respiratory masks to a human head, and, more particularly, to strap members used in such headgear having features to improve the comfort of such strap member when worn by a user.
2. Description of the Related Art
There are numerous situations where it is necessary or desirable to deliver a flow of breathing gas non-invasively to the airway of a patient, i.e., without intubating the patient or surgically inserting a tracheal tube in their esophagus. For example, it is known to ventilate a patient using a technique known as non-invasive ventilation. It is also known to deliver continuous positive airway pressure (CPAP) or variable airway pressure, which varies with the patient's respiratory cycle, to treat a medical disorder, such as sleep apnea syndrome, in particular, obstructive sleep apnea (OSA), or congestive heart failure.
Non-invasive ventilation and pressure support therapies involve the placement of a respiratory patient interface device including a mask component that is typically secured on the face of a patient by a headgear assembly. The mask component may be, without limitation, a nasal mask that covers the patient's nose, a nasal cushion having nasal prongs that are received within the patient's nares, a nasal/oral mask that covers the nose and mouth, or full face mask that covers the patient's face. It is known to maintain such devices on the face of a wearer by a headgear having one or more straps adapted to fit over/around the patient's head. Because such respiratory patient interface devices are typically worn for an extended period of time, it is important for the headgear to maintain the mask component in a desired position while doing so in a manner that is comfortable to the patient.
One example of such a respiratory patient interface device is the Swift LT available from ResMed Inc. FIG. 1 shows an example of such device, generally indicated as 1, which includes a nasal pillows mask 2 adapted to be secured to a patient's head via headgear 4 as shown. Headgear 4 includes a first strap member 6 coupled to nasal mask 2 and disposed generally about an upper portion of a patient's head. Headgear 4 further includes a second strap member 8 that is coupled to first strap member on either side of a patient's head and is disposed below first strap member at about a mid portion of the rear of a patient's head. Such arrangement is generally adequate for securing the mask to the patient's head but still leaves room for improvement.